Foldable and stackable device for spooling flexible tubular pipes The present invention relates to a device for spooling flexible tubular pipes.
The pipes in question are, in particular, the pipes for conveying hydrocarbons laid under water from laying vessels. Such pipes are well known and may be continuous or made of sections connected together. Their rigidity varies and the term "flexible pipes" as used here is understood simply as meaning that they can be spooled into large-diameter reels without plastic deformation.
Flexible tubular pipes are produced in long lengths on land and have to then be transported to the laying site either directly on the laying vessel when the distance between the land-based yard and the laying site is not too great, or generally on an intermediate transport barge which takes them out to the laying vessel.
There are two known types of dockside and on-board containers for spooling the pipes, namely reels and carousels. A reel consists of a horizontal spooling axle held between two cheeks, all of a modest size (for example 9.times.9.times.5 m.sup.3) and capacity (190 tons), while a carousel is defined by a large plate with a vertical-axis central spooling column, all of a very large size (for example 16 m radius) and capacity (2000 tons). While reels can be handled individually with relative ease, carousels cannot. Loading a pipe on board from the dockside is done in one of three ways: either by transporting reels (hereafter termed the reel-reel solution), or by transferring the pipe from dockside reels onto an on-board carousel (hereafter termed the reel-carousel solution), or by transferring the pipe from a dockside carousel onto an on-board carousel (hereafter termed the carousel-carousel solution).
The drawbacks of reels are, on the one hand, that their small diameter demands pipes which are fairly flexible (which allow relatively small minimum bend radius), and that their wound-up length not be too long. If the pipe is stored on board on reels (the reel-reel solution), then the total on board length is modest, and the cost of returning empty reels is high, given the amount of space that is lost. By contrast, the reel-reel solution is particularly flexible when loading dockside, and loading can be carried out quickly and safely.
In the reel-carousel solution, the total on-board length is greater, but the process of transferring reels to carousel is lengthy (which leads to boat downtime costs) and incurs risks of twisting the pipe. Furthermore, returning with the boat's carousel empty is expensive.
The carousel-carousel solution makes it possible to load on board pipes which are both considerably longer and possibly less flexible, although not only is the loading operation slow and inflexible, like in the previous instance, but risks of production coming to a complete standstill in the event of problems with spooling are not completely avoided. The problem of returning empty is not solved either.
Reels with two flanges connected by a hub, and of moderate size and partially foldable, are known in the context of the spooling and transporting of cables or the like. For example, patent FR 2 698 623 A discloses a reel with two flanges, the specific feature of which is that the flanges can be folded along a chord. In documents U.S. Pat. No. 5,649,677 A, U.S. Pat. No. 5,547,147 A, EP 0 745 549 A or DE 35 36555 A, on the other hand, it is the hub which is foldable. These solutions, which at best provide quite a small saving of space in the radial direction of the flanges, cannot be read across to the field of the large-size reels and carousels to which the invention relates.